Inverse opal structure Cs2AgBiBr6 perovskite for toluene catalytic oxidation, preparation method and application

Abstract

The invention relates to an inverse opal structure Cs2AgBiBr6 perovskite for catalytic oxidation of toluene, and a preparation method and application thereof, and the preparation method comprises the following steps: mixing a Cs2AgBiBr6 perovskite solution and a three-dimensional ordered polymer microsphere template, and sequentially removing a solvent and the polymer microsphere template in the obtained intermediate to obtain the inverse opal structure Cs2AgBiBr6 perovskite for catalytic oxidation of toluene. According to the invention, a three-dimensional ordered template structure is constructed by using polymer microspheres with controllable particle size, a perovskite solution is introduced into pores, and a solvent and a template are removed to obtain the Cs2AgBiBr6 inverse opal structure perovskite material with three-dimensional ordered communicated pore channels, so that controllable adjustment of pore size, regular pore structure and good connectivity are realized; the diffusion of reactants and the improvement of light utilization efficiency are facilitated, and the catalytic activity of the catalyst in toluene catalytic oxidation is remarkably improved. The preparation method is simple, the structure is controllable, the method is suitable for large-scale production, and the application prospect is good.

Description

Technical Field

[0001] This invention relates to the field of Cs2AgBiBr6 perovskite technology, and more particularly to an inverse opal structure Cs2AgBiBr6 perovskite for catalytic oxidation of toluene, its preparation method, and its application. Background Technology

[0002] Cs2AgBiBr6 is a typical lead-free dihalide perovskite (A2B′B″X6) composed of Cs ＋ Fill A position, Ag ＋ with Bi 3＋ Alternating occupancy of B sites forms a stable octahedral framework structure. Cs₂AgBiBr₆ perovskite possesses photoelectric properties similar to lead-based perovskites, such as a three-dimensional structure, long carrier lifetime, and relatively small effective carrier mass. It also exhibits high stability and low toxicity, making it a safe and sustainable material among perovskite materials. However, Cs₂AgBiBr₆ materials are mostly dense structures with limited specific surface area and pore connectivity, making it difficult to meet the requirements of efficient mass transfer and light utilization. This limits its application areas and performance to some extent, especially in catalysis. The inverse opal structure is a typical three-dimensional ordered macroporous structure with periodically arranged and interconnected pores, providing continuous transport channels for reactants and products, while also regulating light propagation and scattering behavior at the optical level.

[0003] Toluene is an important basic aromatic hydrocarbon chemical raw material, widely used in petrochemicals, fine chemicals, and materials chemistry. Through the oxidation of toluene, various high-value-added oxygen-containing aromatic compounds such as benzaldehyde, benzoic acid, and benzyl alcohol can be prepared. These products have broad industrial application prospects in pharmaceuticals, fragrances, dyes, and polymer materials. Currently, toluene oxidation typically employs a liquid-phase high-temperature, high-pressure catalytic oxidation process, which suffers from harsh reaction conditions and high energy consumption. Furthermore, current toluene oxidation catalysts generally exhibit shortcomings such as high cost, susceptibility to poisoning, reduced activity under certain temperature conditions, and poor selectivity.

[0004] Therefore, how to provide a Cs2AgBiBr6 material with tunable pore size and its preparation method, and expand its application in the catalytic oxidation of toluene, is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an inverse opal-structured Cs₂AgBiBr₆ perovskite for the catalytic oxidation of toluene, its preparation method, and its applications. This invention constructs an ordered template structure using polymer microspheres with controllable particle size. A Cs₂AgBiBr₆ perovskite solution is introduced into the pores of the three-dimensional ordered template. After solvent and template removal, an inverse opal-structured Cs₂AgBiBr₆ perovskite with three-dimensionally ordered interconnected channels is obtained. This allows for controllable adjustment of the pore size of the inverse opal-structured Cs₂AgBiBr₆ perovskite. The material exhibits a regular pore structure and good connectivity, which is beneficial for reactant diffusion and light utilization efficiency, significantly improving its catalytic activity in the catalytic oxidation of toluene. Furthermore, the preparation method of this invention is simple, the structure is controllable, suitable for large-scale mass production, and has promising application prospects.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene, the method comprising the following steps: S1. Mix Cs2AgBiBr6 perovskite solution with a three-dimensionally ordered polymer microsphere template to obtain an intermediate; S2. Sequentially remove the solvent and the polymer microsphere template from the intermediate described in step S1 to obtain Cs2AgBiBr6 perovskite with an inverse opal structure for the catalytic oxidation of toluene.

[0007] This invention constructs a three-dimensional ordered template structure using polymer microspheres with controllable particle size. A Cs₂AgBiBr₆ perovskite solution is introduced into the pores of this three-dimensional ordered template. After solvent and template removal, an inverse opal structure of Cs₂AgBiBr₆ perovskite with three-dimensionally ordered interconnected channels is obtained. Based on this three-dimensional ordered template structure, the resulting material exhibits a regular pore structure, uniform pore size, and high interconnectivity. Compared to conventional bulk Cs₂AgBiBr₆ perovskite, this improves reactant diffusion and light utilization efficiency, significantly enhancing its catalytic activity in the catalytic oxidation of toluene. Conversely, if a randomly stacked template structure is used, the resulting material has uneven pore size, with a pore structure dominated by stacked pores and localized clusters, resulting in poor connectivity and reduced activity in the catalytic oxidation of toluene.

[0008] As a preferred technical solution of the present invention, the polymer microsphere template in step S1 includes a polystyrene microsphere template.

[0009] It should be noted that the present invention does not impose specific requirements or special limitations on the preparation method of polystyrene microspheres. Conventional preparation processes in the art are applicable to the present invention, and those skilled in the art can make adaptive selections and adjustments according to actual conditions.

[0010] For example, the present invention provides a method for preparing polystyrene microspheres, the method comprising the following steps: A soap-free polymerization method was used, in which styrene monomer and potassium persulfate were added to an aqueous solution under a nitrogen atmosphere, heated and stirred for 12 hours, and then cooled to room temperature to obtain polystyrene microspheres.

[0011] Preferably, the average particle size of the polymer microsphere template in step S1 is 50nm-1000nm, such as 50nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, or 1000nm.

[0012] As a preferred technical solution of the present invention, the method for preparing the three-dimensional ordered polymer microsphere template in step S1 includes: centrifuging the polymer microsphere template solution at high speed, or filtration under pressure and then drying at low temperature to obtain the three-dimensional ordered polymer microsphere template.

[0013] Preferably, the high-speed centrifuge operates at a speed of 12,000 rpm to 20,000 rpm, such as 12,000 rpm, 13,000 rpm, 14,000 rpm, 15,000 rpm, 16,000 rpm, 17,000 rpm, 18,000 rpm, 19,000 rpm, or 20,000 rpm.

[0014] Preferably, the pressure of the pressurized filter is 0.01 MPa-10 MPa, such as 0.01 MPa, 0.03 MPa, 0.05 MPa, 0.1 MPa, 0.3 MPa, 0.5 MPa, 1 MPa, 3 MPa, 5 MPa, 8 MPa or 10 MPa.

[0015] Preferably, the temperature for low-temperature drying is 30℃-70℃, such as 30℃, 35℃, 40℃, 45℃, 50℃, 52℃, 55℃, 58℃, 60℃, 62℃, 65℃, 68℃ or 70℃.

[0016] Preferably, in the polymer microsphere template solution, the mass of the polymer microsphere template contained in 1L of solvent is ≤5g, such as 5g, 4.5g, 4g, 3.5g, 3g, 2.5g, 2g, 1.5g, 1g, 0.5g, or 0.1g.

[0017] In this invention, if the polymer microsphere template contained in 1L of solvent is too high in mass, high-speed centrifugation or pressure filtration will cause the polymer microspheres to randomly stack and fail to form a three-dimensional ordered polymer microsphere template. As a result, the pore structure of the inverse opal structure Cs2AgBiBr6 calcium titanium prepared subsequently is irregular and has poor connectivity.

[0018] As a preferred technical solution of the present invention, the solvent in the Cs2AgBiBr6 perovskite solution in step S1 includes at least one of N,N-dimethylacetamide (DMA), dimethyl sulfoxide (DMSO), or N,N-dimethylformamide (DMF).

[0019] Preferably, in the Cs2AgBiBr6 perovskite solution described in step S1, the mass-to-volume ratio of Cs2AgBiBr6 perovskite to solvent is 1g:(2mL-8mL), for example, 1g:2mL, 1g:2.5mL, 1g:3mL, 1g:3.5mL, 1g:4mL, 1g:4.5mL, 1g:5mL, 1g:6mL, 1g:7mL, or 1g:8mL, etc.

[0020] It should be noted that the Cs2AgBiBr6 perovskite used in this invention can be obtained commercially or prepared by known methods. Those skilled in the art can make adaptive selections and adjustments according to actual needs, such as using an anti-solvent method for preparation.

[0021] As a preferred technical solution of the present invention, the mass-to-volume ratio of the three-dimensional ordered polymer microsphere template and the Cs2AgBiBr6 perovskite solution in step S1 is 1 mg:(0.3 μL-1 μL), for example, 1 mg:0.3 μL, 1 mg:0.4 μL, 1 mg:0.5 μL, 1 mg:0.6 μL, 1 mg:0.7 μL, 1 mg:0.8 μL, 1 mg:0.9 μL, or 1 mg:1 μL, etc.

[0022] In this invention, by controlling the mass-to-volume ratio of the three-dimensionally ordered polymer microsphere template to the Cs2AgBiBr6 perovskite solution to 1 mg:(0.3 μL-1 μL), the filling amount and crystallization process of Cs2AgBiBr6 perovskite in the polymer microsphere template can be precisely controlled. If the mass-to-volume ratio is too low, i.e., the content of Cs2AgBiBr6 perovskite solution is too high, it will cause the template to overflow, forming a dense, blocky Cs2AgBiBr6 perovskite. If the mass-to-volume ratio is too high, i.e., the content of Cs2AgBiBr6 perovskite solution is too low, it will cause the Cs2AgBiBr6 perovskite solution to fail to fully fill the template, resulting in an incomplete material structure and the inability to form a Cs2AgBiBr6 perovskite with a regular pore structure and good connectivity.

[0023] As a preferred technical solution of the present invention, the method for removing the solvent in step S2 includes vacuum decompression.

[0024] Preferably, the vacuum decompression temperature is 50°C-70°C, such as 50°C, 52°C, 55°C, 58°C, 60°C, 62°C, 65°C, 68°C, or 70°C.

[0025] Preferably, the vacuum degree of the vacuum decompression is 0.001mbar-1mbar, such as 0.001mbar, 0.01mbar, 0.1mbar, 0.3mbar, 0.5mbar, 0.8mbar or 1mbar.

[0026] As a preferred technical solution of the present invention, step S2, which involves removing the three-dimensional ordered polymer microsphere template, includes mixing the material after solvent removal with the template removal solvent.

[0027] Preferably, the template removal solvent includes toluene and / or acetone.

[0028] Preferably, before obtaining the inverse opal structure Cs2AgBiBr6 perovskite for toluene catalytic oxidation, the process further includes washing and drying the material after removing the polymer microsphere template.

[0029] It should be noted that the present invention does not impose specific requirements or special limitations on the washing and drying process. Conventional washing and drying processes in the art are applicable to the present invention, and those skilled in the art can make adaptive selections and adjustments according to actual conditions.

[0030] In a second aspect, the present invention also provides an inverse opal structure Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene, wherein the inverse opal structure Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene is prepared according to the preparation method described in the first aspect.

[0031] Thirdly, the present invention also provides an application of an inverse opal structure Cs2AgBiBr6 perovskite, the application comprising using the inverse opal structure Cs2AgBiBr6 perovskite as described in the second aspect for the catalytic oxidation of toluene.

[0032] As a preferred embodiment of the present invention, the catalytic oxidation of toluene is photocatalytic toluene oxidation.

[0033] Preferably, the photocatalytic toluene oxidation is carried out under stirring conditions, and the stirring rate is 100rpm-1000rpm, such as 100rpm, 200rpm, 300rpm, 400rpm, 500rpm, 600rpm, 700rpm, 800rpm, 900rpm or 1000rpm.

[0034] Preferably, the photocatalytic oxidation time of toluene is 0.1h-48h, for example, 0.1h, 1h, 5h, 8h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h or 48h.

[0035] Preferably, the light source for the photocatalytic oxidation of toluene includes an LED light source or a xenon lamp.

[0036] Preferably, the wavelength of the LED light source is 360nm-800nm, such as 360nm, 380nm, 400nm, 420nm, 450nm, 480nm, 500nm, 520nm, 550nm, 580nm, 600nm, 620nm, 650nm, 680nm, 700nm, 720nm, 750nm, 780nm, or 800nm.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention constructs a three-dimensional ordered template structure with controllable polymer microspheres, thereby realizing the controllable adjustment of the pore size of the inverse opal structure Cs2AgBiBr6 perovskite. The preparation method has high precision and flexibility.

[0038] (2) The inverse opal structure Cs2AgBiBr6 perovskite of the present invention has a three-dimensional ordered interconnected macroporous structure, which is conducive to the diffusion of reactants and the improvement of light utilization efficiency, and significantly improves the catalytic activity in the catalytic oxidation of toluene.

[0039] (3) The preparation method of the present invention is simple and the structure is controllable, which is suitable for large-scale mass production and has good repeatability and application prospects. Attached Figure Description

[0040] Figure 1 This is an SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 120 nm provided in Embodiment 1 of the present invention.

[0041] Figure 2 This is an SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 240 nm provided in Embodiment 2 of the present invention.

[0042] Figure 3 This is an SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 360 nm provided in Embodiment 3 of the present invention.

[0043] Figure 4 This is an SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 480 nm provided in Embodiment 4 of the present invention.

[0044] Figure 5This is an SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 600 nm provided in Embodiment 5 of the present invention.

[0045] Figure 6 These are SEM images and EDS distribution diagrams of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 1 of the present invention.

[0046] Figure 7 The images shown are SEM images and EDS distribution diagrams of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 2 of this invention.

[0047] Figure 8 These are SEM images and EDS distribution diagrams of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 3 of the present invention.

[0048] Figure 9 The images shown are SEM images and EDS distribution diagrams of the inverse opal structure Cs2AgBiBr6 perovskite provided in Example 4 of this invention.

[0049] Figure 10 These are SEM images and EDS distribution diagrams of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 5 of the present invention.

[0050] Figure 11 This is the XRD pattern of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 3 of the present invention.

[0051] Figure 12 This is a comparison of the ultraviolet-visible spectra of the inverse opal structure Cs2AgBiBr6 perovskite provided in Example 3 of the present invention and the bulk Cs2AgBiBr6 perovskite provided in Comparative Example 1.

[0052] Figure 13 This is the infrared spectrum of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 3 of the present invention.

[0053] Figure 14 This is a SEM image of the blocky Cs2AgBiBr6 perovskite provided in Comparative Example 1 of this invention. Detailed Implementation

[0054] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0055] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0056] The Cs2AgBiBr6 perovskite used in the specific embodiments of this invention is prepared by the following method: the raw materials are weighed according to the molar ratio of CsBr:AgBr:BiBr3 = 2:1:1 and dissolved in DMSO (dimethyl sulfoxide). The mixture is sonicated until clear, and the sonicated liquid is added dropwise to isopropanol under stirring. A yellow precipitate immediately precipitates out. After centrifugation, the precipitate is dried in an oven at 120°C overnight to obtain Cs2AgBiBr6 perovskite (block form).

[0057] Example 1 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene, the preparation method of which includes the following steps: S1. Add 1g of Cs2AgBiBr6 perovskite to 5mL of DMSO and sonicate to dissolve until a clear liquid is obtained to obtain a Cs2AgBiBr6 perovskite solution. Add the solution containing polystyrene microsphere template to a pressure filter for pressure filtration to obtain a filter cake at a pressure of 0.1MPa. Then place the filter cake in a vacuum drying oven and dry it overnight at 50°C to obtain a three-dimensionally ordered polystyrene microsphere template. Mix 200μL of Cs2AgBiBr6 perovskite solution and 300mg of three-dimensionally ordered polystyrene microsphere template in a flask to obtain an intermediate. S2. The solvent in the intermediate was removed under reduced pressure conditions (0.1 mbar) by constant temperature at 60°C and vacuum pump to obtain a solid sample. The solid sample was then dissolved in 50 mL of toluene, washed and centrifuged three times, and then placed in a vacuum drying oven at 70°C to obtain Cs2AgBiBr6 perovskite with an inverse opal structure.

[0058] The preparation method of the polystyrene microsphere-containing solution template includes the following steps: 3 mL of styrene and 30 mg of potassium persulfate were added sequentially to 500 mL of an aqueous solution under a nitrogen atmosphere. The mixture was heated to 70 °C, stirred at 350 rpm for 12 h, and then cooled. Deionized water was added to obtain a solution containing polystyrene microsphere templates (the average particle size of the polystyrene microsphere templates was 120 nm, and the mass of the polystyrene microsphere templates contained in 1 L of deionized water solvent was 5 g).

[0059] Example 2 This embodiment provides an inverse opal structure Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The preparation method differs from that in Example 1 in that, in step S1, 1g of Cs2AgBiBr6 perovskite is added to 4mL of DMA and ultrasonically dissolved until a clear liquid is obtained to obtain a Cs2AgBiBr6 perovskite solution. The polystyrene microsphere template used has an average particle size of 240nm. The remaining preparation methods and parameters are consistent with those in Example 1.

[0060] The difference between the preparation method of the polystyrene microsphere template solution and Example 1 is that 9 mL of styrene and 30 mg of potassium persulfate are added sequentially to 500 mL of aqueous solution under nitrogen atmosphere, while the rest of the preparation method and parameters are the same as in Example 1.

[0061] Example 3 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The preparation method differs from that in Example 1 in that, in step S1, 1g of Cs2AgBiBr6 perovskite is added to 4mL of DMF and ultrasonically dissolved until a clear solution is obtained to obtain a Cs2AgBiBr6 perovskite solution. The polystyrene microsphere template used has an average particle size of 360nm, and the solution is dried overnight at 70°C. The remaining preparation methods and parameters are consistent with those in Example 1.

[0062] The difference between the preparation method of the polystyrene microsphere template solution and Example 1 is that 25 mL of styrene and 30 mg of potassium persulfate are added sequentially to 500 mL of aqueous solution under nitrogen atmosphere, while the rest of the preparation method and parameters are the same as in Example 1.

[0063] Example 4 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The preparation method differs from that in Example 1 in that, in step S1, the polystyrene microsphere template used has an average particle size of 480 nm. The solution containing the polystyrene microsphere template is centrifuged at 15,000 rpm, the supernatant is discarded, and the solution is dried overnight at 70°C. 500 μL of Cs2AgBiBr6 perovskite solution and 600 mg of three-dimensionally ordered polystyrene microsphere template are mixed in a flask. In step S2, the solid sample is dissolved in 50 mL of acetone. The remaining preparation methods and parameters are consistent with those in Example 1.

[0064] The preparation method of the polystyrene microsphere template solution includes the following steps: 40 mL of styrene and 30 mg of potassium persulfate were added sequentially to 500 mL of an aqueous solution under a nitrogen atmosphere. The mixture was heated to 60 °C, stirred at 400 rpm for 12 h, and then cooled. Deionized water was added to obtain a solution containing polystyrene microsphere templates (the average particle size of the polystyrene microsphere templates was 480 nm, and the mass of the polystyrene microsphere templates contained in 1 L of deionized water solvent was 4 g).

[0065] Example 5 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The preparation method differs from that in Example 1 in that, in step S1, 1g of Cs2AgBiBr6 perovskite is added to a mixture of 3mL DMSO and 3mL LDMF, and the polystyrene microsphere template used has an average particle size of 600nm. The mixture is dried overnight at 70°C. 500μL of Cs2AgBiBr6 perovskite solution and 600mg of three-dimensionally ordered polystyrene microsphere template are mixed in a flask. In step S2, the solid sample is dissolved in 50mL of acetone. The remaining preparation methods and parameters are consistent with those in Example 1.

[0066] The preparation method of the polystyrene microsphere template solution includes the following steps: 60 mL of styrene and 50 mg of potassium persulfate were added sequentially to 500 mL of an aqueous solution under a nitrogen atmosphere. The mixture was heated to 60 °C, stirred at 400 rpm for 12 h, and then cooled. Deionized water was added to obtain a solution containing polystyrene microsphere templates (the average particle size of the polystyrene microsphere templates was 600 nm, and the mass of the polystyrene microsphere templates contained in 1 L of deionized water solvent was 4 g).

[0067] Example 6 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene, the preparation method of which includes the following steps: S1. Add 1g of Cs2AgBiBr6 perovskite to 2mL of DMSO and sonicate until a clear liquid is obtained to get a Cs2AgBiBr6 perovskite solution. Add the solution containing polystyrene microsphere template to a pressure filter for pressure filtration to obtain a filter cake at a pressure of 0.5MPa. Then place the filter cake in a vacuum drying oven and dry it overnight at 50°C to obtain a three-dimensional ordered polystyrene microsphere template. Mix 100μL of Cs2AgBiBr6 perovskite solution and 300mg of three-dimensional ordered polystyrene microsphere template in a flask to obtain an intermediate. S2. The solvent in the intermediate was removed under reduced pressure conditions (vacuum degree of 1 mbar) at constant temperature of 50°C and vacuum pump to obtain a solid sample. The solid sample was then dissolved in 50 mL of toluene, washed and centrifuged three times, and then placed in a vacuum drying oven at 70°C to obtain Cs2AgBiBr6 perovskite with an inverse opal structure.

[0068] The preparation method of the polystyrene microsphere template solution includes the following steps: 1 mL of styrene and 30 mg of potassium persulfate were added sequentially to 500 mL of an aqueous solution under a nitrogen atmosphere. The mixture was heated to 70 °C, stirred at 350 rpm for 12 h, and then cooled. Deionized water was added to obtain a solution containing polystyrene microsphere templates (the average particle size of the polystyrene microsphere templates was 50 nm, and the mass of the polystyrene microsphere templates contained in 1 L of deionized water solvent was 5 g).

[0069] Example 7 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene, the preparation method of which includes the following steps: S1. Add 1g of Cs2AgBiBr6 perovskite to 5mL of DMSO and sonicate until a clear liquid is obtained to get a Cs2AgBiBr6 perovskite solution. Add the solution containing polystyrene microsphere template to a pressure filter for pressure filtration to obtain a filter cake at a pressure of 1MPa. Then place the filter cake in a vacuum drying oven and dry it overnight at 50°C to obtain a three-dimensional ordered polystyrene microsphere template. Mix 300μL of Cs2AgBiBr6 perovskite solution and 300mg of three-dimensional ordered polystyrene microsphere template in a flask to obtain an intermediate. S2. The solvent in the intermediate was removed under reduced pressure conditions (0.5 mbar) by constant temperature at 70°C and vacuum pump to obtain a solid sample. The solid sample was then dissolved in 50 mL of toluene, washed and centrifuged three times, and then placed in a vacuum drying oven at 70°C to obtain Cs2AgBiBr6 perovskite with an inverse opal structure.

[0070] The preparation method of the polystyrene microsphere template solution includes the following steps: 80 mL of styrene and 30 mg of potassium persulfate were added sequentially to 500 mL of an aqueous solution under a nitrogen atmosphere. The mixture was heated to 70 °C, stirred at 350 rpm for 12 h, and then cooled. Deionized water was added to obtain a solution containing polystyrene microsphere templates (the average particle size of the polystyrene microsphere templates was 1000 nm, and the mass of the polystyrene microsphere templates contained in 1 L of deionized water solvent was 3 g).

[0071] Example 8 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The preparation method differs from that in Example 1 in that 990 μL of Cs2AgBiBr6 perovskite solution and 300 mg of three-dimensionally ordered polystyrene microsphere template are mixed in a flask, i.e., the mass-to-volume ratio of the three-dimensionally ordered polymer microsphere template to the Cs2AgBiBr6 perovskite solution is 1 mg: 3.3 μL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0072] Example 9 This embodiment provides an inverse opal-structured Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The preparation method differs from that of Example 1 in that 60 μL of Cs2AgBiBr6 perovskite solution and 300 mg of three-dimensionally ordered polystyrene microsphere template are mixed in a flask, i.e., the mass-to-volume ratio of the three-dimensionally ordered polymer microsphere template to the Cs2AgBiBr6 perovskite solution is 1 mg:0.2 μL. The remaining preparation methods and parameters are consistent with those of Example 1.

[0073] Example 10 This embodiment provides an inverse opal structure Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The preparation method differs from that of Example 1 in that, in step S1, the mass of the polystyrene microsphere template contained in 1L of deionized water solvent is 10g, while the rest of the preparation method and parameters are consistent with those of Example 1.

[0074] Comparative Example 1 This comparative example provides a bulk Cs2AgBiBr6 perovskite, prepared by the above-mentioned antisolvent method.

[0075] Comparative Example 2 This comparative example provides a Cs2AgBiBr6 perovskite for the catalytic oxidation of toluene. The difference between the preparation method and that in Example 1 is that the filter cake obtained by pressure filtration in the form of a polystyrene microsphere template solution is replaced by conventional vacuum filtration. The rest of the preparation method and parameters are the same as in Example 1.

[0076] Figure 1 The image shows a SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 120 nm provided in Embodiment 1 of the present invention. Figure 2 The image shows a SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 240 nm provided in Embodiment 2 of the present invention. Figure 3 This shows a SEM image of the three-dimensionally ordered polystyrene microsphere template with an average particle size of 360 nm provided in Embodiment 3 of the present invention. Figure 4 The image shown is a SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 480 nm provided in Example 4 of the present invention. Figure 5 The image shows an SEM image of a three-dimensionally ordered polystyrene microsphere template with an average particle size of 600 nm provided in Embodiment 5 of the present invention. As can be seen from the above image, the polystyrene microsphere templates used in the present invention are all three-dimensionally ordered and have uniform particle size.

[0077] Figure 6 The SEM image and EDS distribution diagram of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 1 of the present invention are shown. Figure 7The SEM image and EDS distribution diagram of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 2 of the present invention are shown. Figure 8 The SEM image and EDS distribution diagram of each element of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 3 of the present invention are shown. Figure 9 The SEM image and EDS distribution diagram of the inverse opal structure Cs2AgBiBr6 perovskite provided in Embodiment 4 of the present invention are shown. Figure 10 The SEM image and EDS distribution diagram of the inverse opal structure Cs2AgBiBr6 perovskite provided in Example 5 of the present invention are shown. As can be seen from the above figure, the preparation method of the present invention successfully prepared the inverse opal structure Cs2AgBiBr6 perovskite with regular pore structure and good connectivity, and the elements are evenly distributed.

[0078] Figure 11 The XRD pattern of the inverse opal structure Cs2AgBiBr6 perovskite provided in Example 3 of the present invention is shown. As can be seen from the figure, the inverse opal structure Cs2AgBiBr6 perovskite prepared by the preparation method of the present invention corresponds one-to-one with the characteristic peaks in the Cs2AgBiBr6 perovskite standard card, with no obvious impurities, and is a pure phase Cs2AgBiBr6 perovskite.

[0079] Figure 12 The UV-Vis spectrum comparison diagrams of the inverse opal structure Cs2AgBiBr6 perovskite provided in Example 3 of the present invention and the massive Cs2AgBiBr6 perovskite provided in Comparative Example 1 are shown. Figure 13 The infrared spectrum of the inverse opal structure Cs2AgBiBr6 perovskite provided in Example 3 of the present invention is shown. As can be seen from the above figure, the preparation method of the present invention successfully prepared the inverse opal structure Cs2AgBiBr6 perovskite, which has significantly different light absorption properties from conventionally synthesized bulk Cs2AgBiBr6 perovskite.

[0080] Figure 14 The SEM image of the bulk Cs2AgBiBr6 perovskite provided in Comparative Example 1 of the present invention is shown. As can be seen from the figure, the bulk Cs2AgBiBr6 perovskite has a dense structure.

[0081] Application Example 1-10 and Comparative Application Example 1-2 At room temperature, the inverse opal structure Cs2AgBiBr6 perovskite provided in Examples 1-10 and Comparative Examples 1-2 was used as a toluene oxidation catalyst and dispersed in toluene. The amount of inverse opal structure Cs2AgBiBr6 perovskite / Cs2AgBiBr6 perovskite added was 4 mg / mL. The resulting mixture was placed in a stainless steel reactor with a quartz lens, purged with oxygen 5 times, and stirred at 500 rpm for 12 h under LED light with a wavelength of 450 nm. After the reaction was completed, the supernatant was obtained by centrifugation and used for gas chromatography analysis to test the content of benzaldehyde and benzyl alcohol.

[0082] The LED light source was then adjusted to a xenon lamp (simulating sunlight), with all other parameters remaining the same as in Application Example 1. The benzaldehyde and benzyl alcohol contents were then tested, and the specific test results are shown in Table 1.

[0083] Table 1 The test results show that: (1) As can be seen from Application Examples 1-7 and Comparative Application Example 1, the present invention constructs a three-dimensional ordered template structure using polymer microspheres with controllable particle size. The Cs2AgBiBr6 perovskite solution is introduced into the pores of the three-dimensional ordered template. After the removal of the solvent and template, an inverse opal structure Cs2AgBiBr6 perovskite with three-dimensional ordered interconnected channels is obtained. This achieves controllable adjustment of the pore size of the inverse opal structure Cs2AgBiBr6 perovskite. The material has a regular pore structure and good connectivity, which is conducive to the diffusion of reactants and the improvement of light utilization efficiency, and significantly improves the catalytic activity in the catalytic oxidation of toluene.

[0084] Specifically, when using LED lamps, after photocatalytic toluene oxidation, the benzaldehyde content is above 48 μmol, reaching a maximum of 120.3 μmol; the benzyl alcohol content is above 5 μmol, reaching a maximum of 13 μmol; and the total product content is above 53 μmol, reaching a maximum of 133.3 μmol. When using xenon lamps, after photocatalytic toluene oxidation, the benzaldehyde content is above 123 μmol, reaching a maximum of 260 μmol; the benzyl alcohol content is above 11 μmol, reaching a maximum of 19 μmol; and the total product content is above 136 μmol, reaching a maximum of 279 μmol.

[0085] In contrast to the bulk Cs₂AgBiBr₆ perovskite material in Application Example 1, when using an LED lamp for photocatalytic toluene oxidation, the benzaldehyde content was 33.9 μmol, the benzyl alcohol content was 2.2 μmol, and the total product was 36.1 μmol; when using a xenon lamp for photocatalytic toluene oxidation, the benzaldehyde content was 80 μmol, the benzyl alcohol content was 9 μmol, and the total product was 89 μmol. The data comparison shows that using the three-dimensional ordered interconnected pores of the inverse opal structure Cs₂AgBiBr₆ perovskite provided by this invention significantly increases the benzaldehyde and benzyl alcohol content, and the toluene conversion rate is also significantly improved compared to Application Example 1.

[0086] (2) As can be seen from Application Example 1 and Application Examples 8-9, the present invention can precisely control the filling amount and crystallization process of Cs2AgBiBr6 perovskite in the polymer microsphere template by adjusting the mass-volume ratio of the three-dimensional ordered polymer microsphere template and the Cs2AgBiBr6 perovskite solution to 1mg:(0.3μL-1μL). The resulting material has a complete structure and regular pore structure with good connectivity.

[0087] (3) As can be seen from Application Example 1 and Application Example 10, the present invention controls the polymer microsphere template in the solution containing polymer microsphere template to contain ≤5g of polymer microsphere template in 1L of solvent, which can ensure that the polymer microsphere forms a three-dimensional ordered polymer microsphere template and ensure the high-quality preparation of subsequent materials.

[0088] (4) As can be seen from Application Example 1 and Comparative Application Example 2, if the present invention is replaced by conventional vacuum filtration, the polymer microspheres are randomly stacked, the resulting material has uneven pore size, and the pore structure is mainly composed of stacked pores and local cluster pores with poor connectivity. When used for the catalytic oxidation of toluene, the content of benzaldehyde and benzyl alcohol will be greatly reduced.

[0089] In summary, this invention constructs a three-dimensional ordered template structure using polymer microspheres with controllable particle size. A Cs₂AgBiBr₆ perovskite solution is introduced into the pores of this three-dimensional ordered template. After solvent and template removal, an inverse opal-structured Cs₂AgBiBr₆ perovskite with three-dimensionally ordered interconnected channels is obtained. This allows for controllable adjustment of the pore size of the inverse opal-structured Cs₂AgBiBr₆ perovskite. The material exhibits a regular pore structure and good connectivity, which is beneficial for reactant diffusion and improved light utilization efficiency, significantly enhancing its catalytic activity in the catalytic oxidation of toluene. Furthermore, the preparation method of this invention is simple, the structure is controllable, and it is suitable for large-scale mass production, showing promising application prospects.

[0090] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing inverse opal-structured Cs₂AgBiBr₆ perovskite for the catalytic oxidation of toluene, characterized in that, The preparation method includes the following steps: S1. Mix Cs2AgBiBr6 perovskite solution with a three-dimensionally ordered polymer microsphere template to obtain an intermediate; S2. Sequentially remove the solvent and the polymer microsphere template from the intermediate described in step S1 to obtain Cs2AgBiBr6 perovskite with an inverse opal structure for the catalytic oxidation of toluene.

2. The preparation method according to claim 1, characterized in that, The polymer microsphere template mentioned in step S1 includes a polystyrene microsphere template; Preferably, the average particle size of the polymer microsphere template in step S1 is 50 nm to 1000 nm.

3. The preparation method according to claim 1 or 2, characterized in that, The method for preparing the three-dimensional ordered polymer microsphere template in step S1 includes: centrifuging the polymer microsphere template solution at high speed, or filtration under pressure and then drying at low temperature to obtain the three-dimensional ordered polymer microsphere template. Preferably, the rotation speed of the high-speed centrifuge is 12,000 rpm to 20,000 rpm; Preferably, the pressure of the pressure filtration is 0.01 MPa-10 MPa; Preferably, the temperature for the low-temperature drying is 30℃-70℃; Preferably, in the polymer microsphere template solution, the mass of the polymer microsphere template contained in 1L of solvent is ≤5g.

4. The preparation method according to any one of claims 1-3, characterized in that, The solvent in the Cs2AgBiBr6 perovskite solution in step S1 includes at least one of N,N-dimethylacetamide, dimethyl sulfoxide, or N,N-dimethylformamide. Preferably, in the Cs2AgBiBr6 perovskite solution described in step S1, the mass-to-volume ratio of Cs2AgBiBr6 perovskite to solvent is 1 g:(2 mL-8 mL).

5. The preparation method according to any one of claims 1-4, characterized in that, The mass-to-volume ratio of the three-dimensional ordered polymer microsphere template and the Cs2AgBiBr6 perovskite solution in step S1 is 1 mg:(0.3 μL-1 μL).

6. The preparation method according to any one of claims 1-5, characterized in that, Step S2 involves removing the solvent using a vacuum decompression method; Preferably, the temperature of the vacuum decompression is 50°C-70°C; Preferably, the vacuum level of the vacuum decompression is 0.001 mbar to 1 mbar.

7. The preparation method according to any one of claims 1-6, characterized in that, Step S2, the step of removing the polymer microsphere template, includes: mixing the material after solvent removal with the template removal solvent; Preferably, the template removal solvent includes toluene and / or acetone; Preferably, before obtaining the inverse opal structure Cs2AgBiBr6 perovskite for toluene catalytic oxidation, the process further includes washing and drying the material after removing the polymer microsphere template.

8. A Cs₂AgBiBr₆ perovskite with an inverse opal structure for the catalytic oxidation of toluene, characterized in that, The toluene catalytic oxidation method described above is used to prepare Cs2AgBiBr6 perovskite with an inverse opal structure according to any one of claims 1-7.

9. An application of an inverse opal structure Cs2AgBiBr6 perovskite, characterized in that, The application includes using the inverse opal structure Cs2AgBiBr6 perovskite as described in claim 8 for the catalytic oxidation of toluene.

10. The application according to claim 9, characterized in that, The toluene catalytic oxidation is a photocatalytic toluene oxidation. Preferably, the photocatalytic toluene oxidation is carried out under stirring conditions, wherein the stirring rate is 100 rpm-1000 rpm; Preferably, the photocatalytic oxidation time of toluene is 0.1 h to 48 h; Preferably, the light source for the photocatalytic oxidation of toluene includes an LED light source or a xenon lamp; Preferably, the wavelength of the LED light source is 360nm-800nm.

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